The present invention relates generally to the field of electronic circuits and, in particular, to dynamic range extension for electronic circuits.
Electronic systems typically include a large number of modules or electronic circuits. Each electronic circuit provides a specified functionality within the electronic system. Conventionally, electronic circuits process signals that are analog signals, digital signals or both. Converters that transform signals between digital and analog form are commonplace electronic circuits.
One limitation on the operation of these converters is the xe2x80x9cdynamic rangexe2x80x9d of input signals that can be processed by the converters. For purposes of this specification, the term dynamic range refers to the amplitude or magnitude of signals that can be processed by the converter. Typically, converters that have a high dynamic range are also expensive. Less expensive converters typically have a more limited dynamic range. This problem with the dynamic range of converters is particularly relevant in so-called xe2x80x9cbroadbandxe2x80x9d systems that process signals over a high dynamic range over a wide frequency band.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an economical technique to improve the dynamic range of existing electronic circuits, e.g., analog-to-digital (A/D) and digital-to-analog (D/A) converters.
The above-mentioned problems with the dynamic range of electronic circuits and other problems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification. Embodiments of the present invention flatten signals applied to an electronic circuit by selectively controlling the signal level of different frequency bands of the signal so as to extend the dynamic range of an electronic circuit, e.g., the dynamic range of an analog to digital converter.
More particularly, in one embodiment a circuit for extending the dynamic range of an electronic circuit is provided. The circuit includes a first adjustable attenuation circuit having an input and an output and a control input. The control input is adapted to receive a control signal that adjusts the relative gain of the first attenuation circuit. The circuit also includes at least one additional attenuation circuit coupled in parallel with the first adjustable attenuation circuit. The at least one additional attenuation circuit has a control input that is adapted to receive a control signal that adjusts the relative gain of the at least one additional attenuation circuit. The first and the at least one additional attenuation circuits are selectively controlled to adjust the level of signals in different frequency bands so as to extend the dynamic range of signals to be processed by the electronic circuit.